Summary: Electronic and Structural Response of Materials
to Fast Intense Laser Pulses
Roland E. Allen, Traian Dumitrica, and Ben Torralva
Department of Physics, Texas A&M University,
College Station, Texas 77843, USA
Abstract
In this chapter we review theoretical and experimental studies of the subject indicated in
the title: the response of materials to ultrafast and ultra-intense laser pulses. Our primary
emphasis is on the semiconductors GaAs and Si, with some discussion of the fullerene C60.
Near the end there is also a brief discussion of certain molecules.
The theoretical simulations employ tight-binding electron-ion dynamics (TED), a tech-
nique which is fully described in the text. The experiments employ sophisticated techniques
that have been developed during the past 20 years, and which are described in papers cited
in the text. Comparison of the simulations and experiments shows good agreement in all
important respects. In the case of the semiconductors GaAs and Si, there is a nonthermal
phase transition as the intensity is varied at fixed pulse duration. For GaAs, the transition
corresponds to excitation of about 10% of the valence electrons to the conduction band. For
Si, the threshold intensity is approximately the same, but about 15% of the electrons are
excited. These results are qualitatively understandable, because Si has tighter bonding and
a smaller band gap.